Copepod tank population dropped

[Nickola]

Hey all

Could anyone advise on what would cause a successful copepod breeding tank to suddenly start to drop?

They have been breeding loads for a few months. I've not made a changes but have seen there numbers have started to drop considerably.

I do take some out to add to tank, but not as many as they have dropped, they must be drying off..

Any ideas on what could be the issue?
Thanks Nicola

 

[TX_REEF]

lack of food
polluted water
sudden changes in temp, salinity, other parameters (or any other large sudden change?)